Upon operation with an engine-operated machine such as a cutoff saw or an engine cutter for performing an operation of cutting, for example, concrete, a large amount of fine particles of, for example, concrete powder is scattered around the engine-operated machine. If the scattered fine particles adhere to an air filter, the air filter undergoes clogging, and the performance of the engine is reduced. Therefore, the air filter has to be frequently replaced or cleaned, which is a large burden to the operator. Therefore, in Patent Literature 1, a funnel-shaped passage is provided in the upstream of the air filter, and dust is caused to fall by gravity, thereby sending the air with a small amount of dust to the air filter.